The present invention relates to a protected reversing contactor using a multifunctional transmission system for controlling acknowledgement switches.
Generally, reversing contactors of this type comprise, inside a general case, two identical contact maker systems comprising two electromagnets, whose armatures actuate two sets of respective phase switches, whose inputs and outputs are respectively interconnected by two interconnection circuits.
The general principle of such a reversing contactor is well known and will not be described in detail, it being understood that in service only one of the two electromagnets is energized, reversal being obtained by interrupting the power supply to the electromagnet which was energized and by supplying with power the other which was previously inoperative.
Protection of these reversing contactors against prolonged excess currents and overloads is provided by a general protection circuit including a magnetic protection device using, for each phase switch, a magnetic release through the coil of which flows the current passing through this switch, and a thermal protection device comprising bimetallic strips mounted in the phase circuits situated downstream of the output interconnection circuit. Generally, these two protection devices act so as to cause abrupt opening of the set of phase switches via a potential energy release mechanism, following one of the two above current anomalies.
Moreover, these reversing contactors are equipped with a mechanical interlocking system preventing simultaneous closure of the phase switches which, because of the interconnection circuits, would lead to a general short circuit of the mains.
This protection is further completed, in some cases, by the use of acknowledgement switches mounted in series in the circuit supplying the coils of the two electromagnets and which are actuated to cause cut-off of the supply circuit for the electromagnet which is not energized, and thus preventing any possibility of simultaneous energization of the two electromagnets, for example following an erroneous command.
The invention relates more particularly to a reversing contactor of this type in which actuation of the acknowledgement switches is made via a multifunctional transmission system which, in addition to the acknowledgement function, may fulfil other safety functions whose effect is to cause opening of one or both acknowledgement switches.